/// <summary>
/// Adjusts the path (Helmert adjustment).
/// </summary>
/// <param name="dN">Misclosure in northing.</param>
/// <param name="dE">Misclosure in easting.</param>
/// <param name="precision">Precision denominator (zero if no adjustment needed).</param>
/// <param name="length">Total observed length.</param>
/// <param name="rotation">The clockwise rotation to apply (in radians).</param>
/// <param name="sfac">The scaling factor to apply.</param>
void Adjust(out double dN, out double dE, out double precision, out double length,
out double rotation, out double sfac)
{
dN = dE = precision = length = rotation = 0.0;
sfac = 1.0;
// Initialize position to the start of the path, corresponding to the initial
// un-adjusted end point.
IPosition start = m_From;
IPosition gotend = new Position(m_From);
// Initial bearing is due north.
double bearing = 0.0;
// Go through each leg, updating the end position, and getting
// the total path length.
foreach (Leg leg in m_Legs)
{
length += leg.Length.Meters;
leg.Project(ref gotend, ref bearing, sfac);
}
// Get the bearing and distance of the end point we ended up with.
double gotbear = Geom.BearingInRadians(m_From, gotend);
double gotdist = Geom.Distance(m_From, gotend);
// Get the bearing and distance we want.
double wantbear = Geom.BearingInRadians(m_From, m_To);
double wantdist = Geom.Distance(m_From, m_To);
// Figure out the rotation.
rotation = wantbear - gotbear;
// Rotate the end point we got.
gotend = Geom.Rotate(m_From, gotend, new RadianValue(rotation));
// Calculate the line scale factor.
double linefac = m_From.MapModel.SpatialSystem.GetLineScaleFactor(m_From, gotend);
// Figure out where the rotated end point ends up when we apply the line scale factor.
gotend = Geom.Polar(m_From, wantbear, gotdist * linefac);
// What misclosure do we have?
dN = gotend.Y - m_To.Y;
dE = gotend.X - m_To.X;
double delta = Math.Sqrt(dN * dN + dE * dE);
// What's the precision denominator (use a value of 0 to denote an exact match).
if (delta > MathConstants.TINY)
{
precision = wantdist / delta;
}
else
{
precision = 0.0;
}
// Figure out the scale factor for the adjustment (use a value of 0 if the start and end
// points are coincident). The distances here have NOT been adjusted for the line scale factor.
if (gotdist > MathConstants.TINY)
{
sfac = wantdist / gotdist;
}
else
{
sfac = 0.0;
}
// Remember the rotation and scaling factor
m_IsAdjusted = true;
m_Rotation = rotation;
m_ScaleFactor = sfac;
m_Precision = precision;
}
